Palladium nanoparticles encapsulated in core-shell silica: A structured hydrogenation catalyst with enhanced activity for reduction of oxyanion water pollutants

Handle URI:
http://hdl.handle.net/10754/575618
Title:
Palladium nanoparticles encapsulated in core-shell silica: A structured hydrogenation catalyst with enhanced activity for reduction of oxyanion water pollutants
Authors:
Wang, Yin; Liu, Jinyong; Wang, Peng ( 0000-0003-0856-0865 ) ; Werth, Charles; Strathmann, Timothy J.
Abstract:
Noble metal nanoparticles have been applied to mediate catalytic removal of toxic oxyanions and halogenated hydrocarbons in contaminated water using H2 as a clean and sustainable reductant. However, activity loss by nanoparticle aggregation and difficulty of nanoparticle recovery are two major challenges to widespread technology adoption. Herein, we report the synthesis of a core-shell-structured catalyst with encapsulated Pd nanoparticles and its enhanced catalytic activity in reduction of bromate (BrO3-), a regulated carcinogenic oxyanion produced during drinking water disinfection process, using 1 atm H2 at room temperature. The catalyst material consists of a nonporous silica core decorated with preformed octahedral Pd nanoparticles that were further encapsulated within an ordered mesoporous silica shell (i.e., SiO2@Pd@mSiO2). Well-defined mesopores (2.3 nm) provide a physical barrier to prevent Pd nanoparticle (6 nm) movement, aggregation, and detachment from the support into water. Compared to freely suspended Pd nanoparticles and SiO2@Pd, encapsulation in the mesoporous silica shell significantly enhanced Pd catalytic activity (by a factor of 10) under circumneutral pH conditions that are most relevant to water purification applications. Mechanistic investigation of material surface properties combined with Langmuir-Hinshelwood modeling of kinetic data suggest that mesoporous silica shell enhances activity by promoting BrO3- adsorption near the Pd active sites. The dual function of the mesoporous shell, enhancing Pd catalyst activity and preventing aggregation of active nanoparticles, suggests a promising general strategy of using metal nanoparticle catalysts for water purification and related aqueous-phase applications.
KAUST Department:
Biological and Environmental Sciences and Engineering (BESE) Division; Water Desalination and Reuse Research Center (WDRC); Environmental Science and Engineering Program; Environmental Nanotechnology Lab
Publisher:
American Chemical Society (ACS)
Journal:
ACS Catalysis
Issue Date:
3-Oct-2014
DOI:
10.1021/cs500971r
Type:
Article
ISSN:
21555435
Sponsors:
This work was financially supported by the Academic Excellence Alliance (AEA) program at King Abdullah University of Science and Technology (KAUST) and NSF Chemical, Bioengineering, Environmental, and Transport Systems (No. CBET-0746453). We thank Jeffery Bertke and Rudiger Laufhutte (Department of Chemistry at the University of Illinois at Urbana-Champaign (UIUC)) for helping to acquire the XRD patterns and elemental analysis, respectively. We appreciate the help from Ruiqing Lu (UIUC) with obtaining the zeta potential measurements, and Dr. Shaoying Qi (UIUC) for gas adsorption experiments. Technical Assistance at KAUST was provided by Dr. Hongnan Zhang, Dr. Zhonghai Zhang, Mr. Rubal Dua and Mr. Guoying Chen. Four anonymous reviewers provided insightful comments to help improve the presentation of the results in this paper.
Appears in Collections:
Articles; Environmental Science and Engineering Program; Water Desalination and Reuse Research Center (WDRC); Biological and Environmental Sciences and Engineering (BESE) Division

Full metadata record

DC FieldValue Language
dc.contributor.authorWang, Yinen
dc.contributor.authorLiu, Jinyongen
dc.contributor.authorWang, Pengen
dc.contributor.authorWerth, Charlesen
dc.contributor.authorStrathmann, Timothy J.en
dc.date.accessioned2015-08-24T08:34:19Zen
dc.date.available2015-08-24T08:34:19Zen
dc.date.issued2014-10-03en
dc.identifier.issn21555435en
dc.identifier.doi10.1021/cs500971ren
dc.identifier.urihttp://hdl.handle.net/10754/575618en
dc.description.abstractNoble metal nanoparticles have been applied to mediate catalytic removal of toxic oxyanions and halogenated hydrocarbons in contaminated water using H2 as a clean and sustainable reductant. However, activity loss by nanoparticle aggregation and difficulty of nanoparticle recovery are two major challenges to widespread technology adoption. Herein, we report the synthesis of a core-shell-structured catalyst with encapsulated Pd nanoparticles and its enhanced catalytic activity in reduction of bromate (BrO3-), a regulated carcinogenic oxyanion produced during drinking water disinfection process, using 1 atm H2 at room temperature. The catalyst material consists of a nonporous silica core decorated with preformed octahedral Pd nanoparticles that were further encapsulated within an ordered mesoporous silica shell (i.e., SiO2@Pd@mSiO2). Well-defined mesopores (2.3 nm) provide a physical barrier to prevent Pd nanoparticle (6 nm) movement, aggregation, and detachment from the support into water. Compared to freely suspended Pd nanoparticles and SiO2@Pd, encapsulation in the mesoporous silica shell significantly enhanced Pd catalytic activity (by a factor of 10) under circumneutral pH conditions that are most relevant to water purification applications. Mechanistic investigation of material surface properties combined with Langmuir-Hinshelwood modeling of kinetic data suggest that mesoporous silica shell enhances activity by promoting BrO3- adsorption near the Pd active sites. The dual function of the mesoporous shell, enhancing Pd catalyst activity and preventing aggregation of active nanoparticles, suggests a promising general strategy of using metal nanoparticle catalysts for water purification and related aqueous-phase applications.en
dc.description.sponsorshipThis work was financially supported by the Academic Excellence Alliance (AEA) program at King Abdullah University of Science and Technology (KAUST) and NSF Chemical, Bioengineering, Environmental, and Transport Systems (No. CBET-0746453). We thank Jeffery Bertke and Rudiger Laufhutte (Department of Chemistry at the University of Illinois at Urbana-Champaign (UIUC)) for helping to acquire the XRD patterns and elemental analysis, respectively. We appreciate the help from Ruiqing Lu (UIUC) with obtaining the zeta potential measurements, and Dr. Shaoying Qi (UIUC) for gas adsorption experiments. Technical Assistance at KAUST was provided by Dr. Hongnan Zhang, Dr. Zhonghai Zhang, Mr. Rubal Dua and Mr. Guoying Chen. Four anonymous reviewers provided insightful comments to help improve the presentation of the results in this paper.en
dc.publisherAmerican Chemical Society (ACS)en
dc.subjectbromateen
dc.subjectcore-shellen
dc.subjectmesoporous silicaen
dc.subjectoxyanionen
dc.subjectpalladium nanoparticleen
dc.subjectwater purificationen
dc.titlePalladium nanoparticles encapsulated in core-shell silica: A structured hydrogenation catalyst with enhanced activity for reduction of oxyanion water pollutantsen
dc.typeArticleen
dc.contributor.departmentBiological and Environmental Sciences and Engineering (BESE) Divisionen
dc.contributor.departmentWater Desalination and Reuse Research Center (WDRC)en
dc.contributor.departmentEnvironmental Science and Engineering Programen
dc.contributor.departmentEnvironmental Nanotechnology Laben
dc.identifier.journalACS Catalysisen
dc.contributor.institutionDepartment of Civil and Environmental Engineering, University of Illinois at Urbana-ChampaignUrbana, IL, United Statesen
dc.contributor.institutionDepartment of Civil and Environmental Engineering, University of Wisconsin-MilwaukeeMilwaukee, WI, United Statesen
dc.contributor.institutionDept. of Civil, Architectural and Environmental, Engineering University of Texas at AustinAustin, TX, United Statesen
kaust.authorWang, Pengen
All Items in KAUST are protected by copyright, with all rights reserved, unless otherwise indicated.